1. Field of the Invention
The invention generally relates to modems and communication devices, and more particularly relates to a device for emulating telephone functions using a modem, a host computer, and a headset having a microphone and earphones. The communication device may be a telephone, cellular radio or any other communication device using visible light, infrared, ultraviolet, radio or acoustic waves.
2. Description of Related Art
Modems are commonly employed for allowing a host computer to input and output data to other devices through a telephone line connected to the public switched telephone network (PSTN). Traditionally, modems allowed for only data communication in the form of encoded data or facsimile data. To allow for ordinary, voice telephone calls, a separate telephone is needed for direct connection into the PSTN.
More recently modems have been developed which incorporate voice telephonic features. One such device is a data/fax/voice modem. The data/fax/voice modem automatically answers an incoming telephone call received along a telephone line connected to the PSTN. The data/fax/voice modem then determines whether the received telephone call includes a data message, a facsimile message, or an ordinary voice message. If the incoming message is a data message, a data modem module of the data/fax/voice modem operates to receive and decode the data message for storage in a computer memory of a host computer such as a hard disk drive. If the incoming message is a facsimile message, a fax module of the data/fax/voice modem operates to receive and decode the facsimile image for storage within the memory of the host computer. Alternatively, a facsimile print-out device may be connected to the data/fax/voice modem for automatically printing the facsimile image, thus eliminating the need to store the facsimile image within the host computer. If the incoming message is a voice message, an answering machine module of the data/fax/voice modem operates to answer the incoming voice communication. Initially, the answering machine module of the data/fax/voice modem outputs a prerecorded greeting, then records a voice message in response to the greeting. A digital-to-analog converter means is typically included within the data/fax/voice modem for converting the incoming voice message to digital signals for storing in the memory of the host computer. Alternatively, the data/fax/voice modem may be connected to a conventional analog recording device, such as a tape recorder for recording the voice message. As can be appreciated, a variety of implementations and configurations are available.
To allow an operator to listen to received voice messages and to record the answering machine greeting, a telephone headset is typically provided. The telephone headset, which includes an earphone and a microphone, is connected directly into the modem. However, no capability is provided for receiving or placing a voice telephone call using just the headset, modem and host computer. To be able to place telephone calls or to converse directly with a calling party, a separate telephone is required for connection to the PSTN line.
FIG. 1 illustrates a set-up wherein a telephone is provided in combination with a modem. More specifically, FIG. 1 illustrates a set-up having a modem 10, a host computer 12, a telephone headset 14, and a separate telephone 16. As can be seen, telephone 16 is directly connected to a telephone line 18 interconnecting the PSTN and modem 10. In some systems, telephone 16 is directly connected into modem 10. However, even in such systems, internal circuitry bypasses the modem operations to provide only a direct interconnection between telephone 16 and telephone line 18.
Although the setup of FIG. 1 provides for both placing and receiving voice telephone messages, the setup is not ideal. For example, undesirable redundancy results from a need to provide both a complete telephone 16 and a separate telephonic headset 14. In particular, two sets of speaker and microphone mechanisms are required, one on the headset and one on the telephone. Moreover, much of the functionality of the telephone, including call initiation, dialing, repertory dialing and call answering, are duplicated within the modem and the telephone. Another disadvantage is that a large bulky telephone is required to conduct ordinary voice communications. Carrying such a large telephone may not be practical, especially for portable applications. Moreover, the physical size of a standard module telephone jack is difficult to incorporate into small form-factor modems and other devices. To avoid these and other disadvantages, it would be desirable to provide a mechanism which would allow modem 10, host computer 12 and headset 14 to emulate the telephone, thereby eliminating the need to provide a separate telephone.
Similar disadvantages occur with other communications devices, besides modems, such as facsimile machines and personal digital assistant systems (PDA's).
Non-land-line based communication media have been employed for transmitting telephonic communications. Examples include cellular radio and related devices. Other examples include non-hard-wired local area networks (LAN's) which may employ radio or infrared signaling. The above-described disadvantages in conventional modems can occur in non-land-line based devices and are not limited solely to land based telephone lines or to the PSTN telephone network.